Process for introducing a stabilizing element into a vertebral column

ABSTRACT

A process for introducing a stabilizing element into a vertebral column, in which the stabilizing element is introduced in such a manner that the stabilizing element connects two adjacent vertebral bodies to one another.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application relates to, European Application Serial No. XXX(attorney docket No. WESTP.EU001) and relates to European ApplicationSerial No. YYY (attorney docket No. WESTP.EU002), filed on even dateherewith, the entire contents of each of which are incorporated hereinfully by reference.

FIGURE FOR PUBLICATION

TBD.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a process for introducing a stabilizingelement into a vertebral column as well as the process for introducingan intervertebral disk prosthesis into an intervertebral space.

2. Description of the Related Art

It is known that a vertebral column can be stabilized in that adjacentvertebral bodies are connected to each other by a rod system. To thisend, several, in particular four, pedicle screws are insertedtransversely to the longitudinal axis of the vertebral column into theadjacent vertebral bodies and each two pedicle screws of adjacentvertebral bodies are connected to one another by a rod. Such astabilization requires a considerable intervention in the patient andentails as a rule a soft-tissue trauma over a length of 10 cm or more.

It is furthermore known that an intervertebral disk prosthesis can beintroduced between two adjacent vertebral bodies in order to replace adefective intervertebral disk. In order to insert such a intervertebraldisk prosthesis, various operation procedures were developed. Thebest-known processes are the ventrally performed vertebral body fusion,called ALIF (anterior lumbar interbody fusion), the dorsally performedvertebral body fusion, called PLIF (posterior lumbar interbody fusion)and the transforaminal vertebral body fusion, performed via adorsolateral access, called TLIF (transforaminal lumbar interbodyfusion) (cf. FIG. 49). These interventions also require a considerableintervention in the patient.

The invention solves the problem by making available a process for thestabilizing of a vertebral column that brings about a reliablestabilization of the vertebral column with few components and that inparticular causes only a slight trauma to the soft tissue.

The invention solves the problem with a process for the introduction ofa stabilizing element into a vertebral column as well as with a processfor introducing an intervertebral disk prosthesis into an intervertebralspace between two adjacent vertebral bodies.

ASPECTS AND SUMMARY OF THE INVENTION

The process in accordance with the invention for introducing astabilizing element into a vertebral column is distinguished in that thestabilizing element is introduced in such a manner that the stabilizingelement connects two adjacent vertebral bodies to one another. Theconnection takes place, in particular, directly via the stabilizingelement. Thus, there is the possibility of stabilizing a vertebralcolumn, in particular two adjacent vertebral bodies with a singlestabilizing element.

According to a preferred embodiment of the invention, the stabilizingelement passes through each of the two adjacent vertebral bodies in thelongitudinal direction of the vertebral column at least in sections. Asa result, a direct connection of the two adjacent vertebral bodies isdirectly achieved by the stabilizing element itself. Thus, a pluralityof components to be introduced, such as is necessary in a rod system, iseliminated.

The stabilizing element is introduced in an especially advantageousmanner through a single access point so that the intervention can takeplace in particular in a minimally invasive manner and severe trauma tothe soft tissue can be avoided in the patient. The access point ispreferably dorso-medially arranged.

A reliable stabilization of the two adjacent vertebral bodies relativeto one another is preferably achieved in that the stabilizing element isintroduced in such a manner that it passes through the one, inparticular the superior one, of the two adjacent vertebral bodies andthat one end of the stabilizing element comes to rest in the other, inparticular the inferior one, of the two adjacent vertebral bodies.

The stabilizing element is preferably introduced in such a manner thatit comes to lie on a connection line between a pedicle of the superiorone of the two adjacent vertebral bodies and between a point in theinferior third of the anterior edge of a sagittal section of theinferior one of the two adjacent vertebral bodies, or that it comes tolie on a connection line between a pedicle of the inferior one of thetwo adjacent vertebral bodies and between a point in the superior thirdof the anterior edge of a sagittal section of the superior one of thetwo adjacent vertebral bodies. The stabilizing element connects the twovertebral bodies thereby in a reliable manner and can be introducedthrough a single access point.

The stabilizing element is preferably introduced in such a manner thatit lies, when viewed from the dorsal in the sagittal direction, on aline that has an entrance point between 9 and 11 o'clock and an exitpoint between 4 and 6 o'clock on a pedicle clock of the superiorvertebral body, or that has an entrance point between 1 and 3 o'clockand an exit point between 6 and 8 o'clock on a pedicle clock of thesuperior vertebral body, or that has an entrance point between 7 and 9o'clock and an exit point between 12 and 2 o'clock on a pedicle clock ofthe inferior vertebral body, or that has an entrance point between 3 and5 o'clock and an exit point between 10 and 12 o'clock on a pedicle clockof the inferior vertebral body. This position of the stabilizing elementachieves a reliable stabilization of the two vertebral bodies relativeto one another.

The stabilizing element is preferably introduced along a guide wire,which facilitates the positioning of the stabilizing element.

According to a preferred environment of the invention, the relativeposition of the two adjacent vertebral bodies can be varied relative toone another by the stabilizing element, which can bring about a desiredstabilization of the vertebral column in a simple manner.

The stabilizing element is preferably constructed as a bone screw thatcan be introduced in an especially simple manner and finds a good holdin the vertebral bodies by the threading.

The bone screw is advantageously inserted into a casing that has asection with an outer threading. The casing brings about an additionalstabilization of the bone screw in the vertebral body.

The bone screw is especially preferably inserted into a casing that hasa front section, a middle section and a rear section, whereby the frontsection has an outer threading and at least one spreading element isarranged in the middle section. After the insertion of the casing, thespreading elements can be spread open in order to stabilize, forexample, straighten out one of the vertebral bodies through which thecasing is guided.

According to a preferred embodiment of the invention, an intervertebraldisk prosthesis is inserted between the two adjacent vertebral bodiesthrough which prosthesis the stabilizing element passes. In this manner,an additional stabilization of the vertebral column can be achieved andin particular a stabilization of the intervertebral disk prosthesis andthe bone screw relative to one another can be achieved.

The intervertebral disk prosthesis is especially preferably constructedsubstantially U-shaped with a first shank and a second shank, wherebythe two shanks can be pivoted relative to one another. This makespossible a minimally invasive introduction of the intervertebral diskprosthesis. In particular, at first the intervertebral disk prosthesisand subsequently the bone screw can be inserted, or also at first thebone screw and subsequently the intervertebral disk prosthesis can beinserted.

The process in accordance with the invention for introducing anintervertebral disk prosthesis into an intervertebral space between twoadjacent vertebral bodies is distinguished in that the intervertebraldisk prosthesis is introduced through a single extraforaminal accesspoint. Thus, the access point lies further dorsally, however, at such alarge angle to the sagittal plane that the access is not guided throughthe foramen but rather an introduction of the intervertebral diskprosthesis into the intervertebral space is laterally possible (cf. FIG.49). A damaging of the foramen and a significant trauma to the softtissue of the patient are therefore avoided. This operation procedure istherefore designated as EFOLIF (extraforaminal interbody fusion).

Nerve roots present between the extraforaminal access point and theintervertebral space are pressed either inferior-medially orsuperior-laterally. If the nerve roots are pressed inferior-medially, orcauda-dorsally, the operation procedure is designated as EPAPINLIF(extraforaminal parapedicular inferior interbody fusion), whereas theoperation procedure in which the nerve roots are pressedsuperior-laterally or ventro-cranially is designated as EPAPSULIF(extraforaminal parapedicular superior interbody fusion).

According to an advantageous further development of the intervertebral afirst fixation screw is introduced through the extraforaminal accesspoint transpedicularly or extrapedicularly. This eliminates furtheraccesses for the introduction of fixation screws for fastening a rodsystem.

A second fixation screw is preferably introduced through theextraforaminal access point extrapedicularly. This eliminates furtheraccesses for the introduction of fixation screws for fastening a rodsystem.

An advantageous environment of the invention provides that the firstfixation screw is attached to the inferior one of the two adjacentvertebral bodies and that the second fixation screw is attached to thesuperior one of the two adjacent vertebral bodies, and that a rod isfastened to the first fixation screw and to the second fixation screw.This makes it possible to introduce the intervertebral disk prosthesisthrough a single access as well as the fastening of a rod system.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in detail using the following figures:

FIG. 1a shows a front view of two adjacent vertebral bodies.

FIG. 1b shows a lateral view of the two vertebral bodies according toFIG. 1 a.

FIG. 2a shows a lateral view of two adjacent vertebral bodies.

FIG. 2b shows a top view onto the two virtual bodies in accordance withFIG. 2 a.

FIG. 3 shows a perspective view of a first exemplary embodiment of acasing.

FIG. 3a shows a top view onto the rear end of the casing according toFIG. 3;

FIG. 4 shows the casing according to FIG. 3 with a screw to beintroduced therein.

FIG. 5 shows the casing according to FIG. 3 with a screw set therein.

FIG. 6 shows the casing according to FIG. 3 with a screwing-ininstrument sets on it.

FIG. 7 shows a perspective view of a second exemplary embodiment of acasing.

FIG. 8 shows the casing according to FIG. 7 in the spread-open state.

FIG. 9 shows a lateral view of the casing according to FIG. 7.

FIG. 10 shows a sectional enlargement of the casing according to FIG. 7.

FIG. 11 shows a lateral view of a third exemplary embodiment of acasing.

FIG. 12 shows the casing according to FIG. 11 in partial section.

FIG. 13 shows a top view onto the rear end of the casing according toFIG. 11,

FIG. 14 shows the casing according to FIG. 11 in a partiallyscrewed-in-state.

FIG. 15 shows the casing according to FIG. 11 in the screwed-in-state.

FIG. 16 shows another view of the casing according to FIG. 15.

FIG. 17 shows a longitudinal section through the casing according toFIG. 11.

FIG. 18 shows a schematic view of the casing according to FIG. 3 in astate inserted in a vertebral body.

FIG. 19 shows a schematic view of the casing according to FIG. 11 in astate inserted in a vertebral body.

FIG. 20 shows the casing according to FIG. 19 in a state screwed furtherinto a vertebral body.

FIG. 21 shows a front view of the casing according to FIG. 20 in a stateinserted in a vertebral body.

FIG. 22 shows a schematic view of a first exemplary embodiment of anintervertebral disk prosthesis.

FIG. 23 shows a schematic view of a second exemplary embodiment of anintervertebral disk prosthesis.

FIG. 24 shows a schematic view of a third exemplary embodiment of anintervertebral disk prosthesis.

FIG. 25 shows a schematic view of a fourth exemplary embodiment of anintervertebral disk prosthesis.

FIG. 26 shows a schematic view of a fifth exemplary embodiment of anintervertebral disk prosthesis.

FIG. 27 shows a side view of the intervertebral disk prosthesisaccording to FIG. 26.

FIG. 28 shows the intervertebral disk prosthesis according to FIG. 26 ina pivoted-open state.

FIG. 29 shows a schematic perspective view of a sixth exemplaryembodiment of an intervertebral disk prosthesis.

FIG. 30 shows a top view onto the intervertebral disk prosthesisaccording to FIG. 29 in the folded-together state.

FIG. 31 shows the intervertebral disk prosthesis according to FIG. 29 ina pivoted-open state.

FIG. 32 shows a perspective view of the spring element of theintervertebral disk prosthesis according to FIG. 30.

FIG. 33 shows a perspective view of the intervertebral disk prosthesisaccording to FIG. 29 in a spread-open state.

FIG. 34 shows a top view onto the disassembled intervertebral diskprosthesis according to FIG. 29.

FIG. 35 shows the intervertebral disk prosthesis according to FIG. 29 ina folded-together state that is inserted into a holder.

FIG. 36 shows the intervertebral disk prosthesis according to FIG. 29 ina spread-open state that is inserted into a holder.

FIG. 37 shows the intervertebral disk prosthesis according to FIG. 29with the holder separated from it.

FIG. 38 shows a view of the introduction of the intervertebral diskprosthesis according to FIG. 29 into an intervertebral space.

FIG. 39 shows another view of the insertion of the intervertebral diskprosthesis according to FIG. 29 into an intervertebral space.

FIG. 40 shows another view of the insertion of the intervertebral diskprosthesis according to FIG. 29 into an intervertebral space.

FIG. 41 shows another view of the insertion of the intervertebral diskprosthesis according to FIG. 29 into an intervertebral space.

FIG. 42 shows another view of the insertion of the intervertebral diskprosthesis according to FIG. 29 into an intervertebral space.

FIG. 43 shows the intervertebral disk prosthesis according to FIG. 29 inthe state inserted into the intervertebral space with a schematicperspective view of a bone screw.

FIG. 44 shows a side view of the intervertebral disk prosthesis in thestate inserted into the intervertebral space between two adjacentvertebrae with a schematic view of the bone screw.

FIG. 45 shows a seventh exemplary embodiment of an intervertebral diskprosthesis with holder.

FIG. 46 shows the intervertebral disk prosthesis according to FIG. 45with holder.

FIG. 47 shows the intervertebral disk prosthesis according to FIG. 45with an alternative spring element.

FIG. 48 shows the intervertebral disk prosthesis according to FIG. 47 inanother position.

FIG. 49 shows a schematic view of different access paths.

FIG. 50 shows a schematic view of the extraforaminal access path.

FIG. 51 shows another schematic view of the extraforaminal access path.

FIG. 52 shows a schematic view of the vertebral body with attached firstfixation screw.

FIG. 53 shows a schematic view of the vertebral body with an attachedsecond fixation screw.

FIG. 54a shows a schematic view of the vertebral body with attached rod.

FIG. 54b shows a schematic view of the vertebral body with attached rodwith the first fixation screw in an alternative position.

FIG. 55 shows a side view of a fourth exemplary embodiment of a casingwith a screw inserted in it.

FIG. 56 shows the casing according to FIG. 55 with an only partiallyinserted screw.

FIG. 57 shows the casing according to FIG. 55 with the screw accordingto FIG. 55.

FIG. 58 shows a schematic view of the screw according to FIG. 57 in astate inserted into a vertebral body.

FIG. 59 shows the screw according to FIG. 57, onto which the casingaccording to FIG. 57 is screwed on.

FIG. 60 shows the screw according to FIG. 57 onto which the casingaccording to FIG. 57 is screwed on with another position of the casing.

FIG. 61 shows the screw according to FIG. 57 onto which the casingaccording to FIG. 22 is screwed on with another position of the casing.

FIG. 62 shows the screw according to FIG. 57 onto which the casingaccording to FIG. 57 is screwed on with another position of the casing.

In the figures, the same reference numerals designate parts that areidentical or identical in nature. For the sake of clarity, not allreference numerals are indicated in all figures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 a, 1 b and 2 a, 2 b show two adjacent vertebral bodies 100, 200,whereby vertebral body 100 forms the superior vertebral body andvertebral body 200 forms the inferior vertebral body. An intervertebralspace 250 is arranged between the two vertebral bodies 100, 200. Inorder to be able to reestablish the stability of the vertebral column,for example, in the case of a defective intervertebral disk, in manyoperation procedures the two adjacent vertebral bodies 100, 200 and arerigidly connected to one another. According to the process in accordancewith the invention, the connection of the two adjacent vertebral bodies100, 200 takes place by means of a stabilizing element that directlyconnects the two adjacent vertebral bodies 100, 200 to one another. Theconnection takes place in particular in such a manner that thestabilizing element passes through each of the two adjacent vertebralbodies 100, 200 in the longitudinal direction of the vertebral column atleast in sections so that in particular rod systems with severalcomponents arranged on the back side of vertebral bodies 100, 200 areavoided.

The stabilizing element is introduced in a first alternative alongconnection line 700 shown in FIGS. 1a and 1 b. In this alternative, theintroduction takes place from the cranial to the caudal. Theintroduction is possible through a single access point arranged inparticular dorso-medially. As can be recognized, in particular in FIG. 1b, connection line 700 runs between a pedicle of superior vertebral body100 and a point in the inferior, alternatively also in the superior,third of the anterior edge of a sagittal section of the inferiorvertebral body 200. The sagittal section does not have to runsymmetrically through the vertebral bodies 100, 200 but rather can alsorun parallel to them in an offset manner. As can be recognized in FIG.1, connection line 700 has an entrance point between 9 and 11 o'clockand an exit point between 4 and 6 o'clock viewed dorsally in thesagittal direction on a pedicle clock 800 of superior vertebral body100. Of course, the stabilizing element can also be introducedmirror-symmetrically to the sagittal plane and thus connection line 700has an entrance point between 1 and 3 o'clock and an exit point between6 and 8 o'clock on a pedicle clock of superior vertebral body 100. Aclock arranged in an imaginary manner on a pedicle is considered aspedicle clock 800, which can be recognized in a front view and whoseconnection line runs between its 12 and its 6 approximately parallel tothe longitudinal axis of the vertebral column.

If a stabilizing element is introduced along connection line 700, itpasses at first through superior vertebral body 100 until a distal endof the stabilizing element comes to lie in inferior vertebral body 200,so that the two vertebral bodies 100, 200 can be directly connected toone another by the stabilizing element in this manner.

In order to be able to insert the stabilizing element, at first thepoint on superior vertebral body 100 is determined on which theimaginary pedicle clock 800 is arranged, and the alignment of connectionline 700 is determined. A bearing is taken on the pedicle on whichconnection line 700 enters into superior vertebral body 100 inparticular in the anterior-posterior beam path and on the vertebralspine of inferior vertebral body 200. At first, a guide wire isintroduced along connection line 700. Finally, the stabilizing elementis introduced along the guide wire.

The stabilizing element is introduced in a second alternative alongconnection line 700′ shown in FIGS. 2a and 2b . In this alternative theintroduction takes place from caudal to cranial. The introduction ispossible through a single access point that is arranged in particulardorso-medially. As can be recognized in particular in FIG. 2a ,connection line 700′ runs between a pedicle of inferior vertebral body200 and a point in the inferior, alternatively also in the superior,third of the anterior edge of a sagittal section of superior vertebralbody 200. The sagittal section does not have to run symmetricallythrough vertebral bodies 100, 200 but rather can also run parallel tothem in an offset manner. Connection line 700′ has an entrance pointbetween 7 and 9 o'clock and an exit point between 12 and 2 o'clock whenviewed from the dorsal in the sagittal direction on a pedicle clock ofinferior vertebral body 200. Of course, the stabilizing element can alsobe introduced mirror-symmetrically to the sagittal plane and thusconnection line 700 has an entrance point between 3 and 5 o'clock anexit point between 10 and 12 o'clock on a pedicle clock of the inferiorvertebral body.

If a stabilizing element is introduced along connection line 700′, itpasses at first through inferior vertebral body 200 until a distal endof the stabilizing element comes to lie in superior vertebral body 100,so that in this manner the two vertebral bodies 100, 200 are directlyconnected to one another by the stabilizing element.

In order to be able to insert the stabilizing element, at first thepoint on the inferior vertebral body 200 is determined at whichimaginary pedicle clock 800 is arranged and the alignment of connectionline 700′ determined. A bearing is taken on the pedicle at whichconnection line 700′ enters into inferior vertebral body 200, inparticular in the anterior-posterior beam path, and on the vertebralspine of superior vertebral body 100. At first, a guide wire isintroduced along connection line 700.′ Finally, the stabilizing elementis introduced along the guide wire.

Alternatively, or additionally, to the stabilizing element that is used,in particular in accordance with one of the two previously describedprocesses, an intervertebral disk prosthesis can be used. This takesplace via an operation procedure in accordance with the invention inwhich the intervertebral disk is introduced through a singleextraforaminal access point. The access point is therefore locatedfurther dorsally, but at such a large angle to the sagittal plane thatthe access is not guided through the foramen but rather an introductionof the intervertebral disk prosthesis into intervertebral space 250 islaterally possible (cf. FIGS. 49 and 51). The intervertebral diskprosthesis can be laterally introduced from the right as well as fromthe left. This avoids damage to the foramen and severe trauma to thesoft tissue of the patient. This operation process is thereforedesignated as EFOLIF (extraforaminal interbody fusion). Nerve rootspresent between the extraforaminal access point and intervertebral space250 are pressed either inferior-medially or superior-laterally. This isshown in particular in FIG. 50. A surgical instrument 260 a is used topress a nerve root 270 arranged between the access point andintervertebral space 250 superior-laterally or, expressed another terms,ventro-cranially. This operation procedure is designated as epapsulif(extraforaminal parapedicular superior interbody fusion). A surgicalinstrument 260 b is used to press a nerve root 270 arranged between theaccess point and intervertebral space 250 alternativelyinferior-medially or, expressed another terms, caudo-dorsally. Thisoperation procedure is designated as EPAPINLIF (extraforaminalparapedicular inferior interbody fusion). The intervertebral diskprosthesis can be introduced laterally into intervertebral space 250 inthe EPAPINLIF process as well as in the EPAPSULIF process (cf. FIG. 51)without damaging the forearm and as in traditional transforaminalprocesses.

In addition, the extraforaminal access point through which theintervertebral disk prosthesis is introduced also makes possible anintroduction of a rod system if the intervertebral disk prosthesis isnot to be used in combination with the previously described stabilizingelement that directly connects the two adjacent vertebral bodies 100,200 to one another. In order to fasten the rod system, a first fixationscrew 280 is introduced transspedicularly, i.e., through a pedicle ofthe vertebral body, in particular of superior vertebral body 100,through the extraforaminal access point (FIG. 52). Furthermore, a secondfixation screw 285 is introduced extrapedicularly, i.e., not through thepedicle, but rather transversely to the pedicle through theextraforaminal access point, in particular into inferior vertebral body200 (cf. FIG. 53). Fixation screws 280, 285 are designed in such amanner that a rod can be attached to their heads so that after theintroduction of fixation screws 280, 285 a rod 286 is fastened to thefirst fixation screw 280 and to the second fixation screw 285 for arigid connection of the two adjacent vertebral bodies 100, 200 (cf. FIG.54a ). Alternatively, as shown in FIG. 54 b, the first fixation screw280 can also be fastened extrapedicularly in superior vertebral body 100(cf FIG. 54b ).

Embodiments of the stabilizing element are described in the following.

FIGS. 3 to 6 show different views of a first exemplary embodiment of acasing 10 with a front section 11, a central area 12 following it andwith a following rear area 13. Front area 11 carries an outer threading14. Rear area 13 is designed smooth on its outer side or optionallystructured in the longitudinal direction. Several slots 15 are arrangedin the central area in the longitudinal direction of casing 10 betweenwhich spreading elements 16 are formed. In the present instance, slots15 are arranged regularly distributed over the circumference. A total offour spreading elements 16 are formed; however, the number of spreadingelements 16 can also be higher or lower. In particular, spreadingelements 16 can also be arranged and formed asymmetrically over theouter circumference of casing 10.

A first inner threading is arranged in front area 11 of casing 10 whichspreading has a first pitch. A screw 20 can be screwed into casing 10,in particular into the first inner threading of casing 10, which screwhas a shaft 20 a and a head 20 b. Shaft 20 a has a front section 21, afollowing central area 22 and rear section 23 following the latter,whereby head 20 b follows rear section 23. A first outer threading 24 isarranged in front section 21 of screw 20 whereas a second outerthreading 25 is arranged in rear section 23. The first outer threading24 has a third pitch whereas the second outer threading 25 has a fourthpitch. However, the third pitch of first outer threading 24 correspondsin particular to the first pitch of the first inner threading of casing10. The third pitch and the fourth pitch are selected differently sothat screw 20 acts as a traction screw or compression screw. When screw20 is screwed into casing 10, as is apparent in particular in FIG. 5,the first section 11 is drawn against rear section 13 by the differentpitches of the first and second outer threadings 24, 25, wherebyspreading elements 16 arranged in the central range spread radiallyoutward. Spreading elements 16 have set kinks 17 that are intended toensure a defined spreading open of spreading elements 16.

Casing 10 can also have only front section 11 with outer threading 14without the following central and rear areas 12, 13 (not shown) in orderto bring about a stabilization of screw 20 in the vertebral body.

A screwdriver instrument 40 is used to insert casing 10 into vertebralbodies 100, 200 (cf. FIG. 18). Casing 10 has an out-of-round contour 18on its one end, especially on the free end of rear section 13 (cf. FIG.3a ), in which contour a correspondingly formed contour of screwdriverinstrument 40 engages in order to screw the casing into vertebral bodies100, 200. As is apparent from FIG. 18, in which two adjacent vertebralbodies 100, 200 are schematically shown with an intervertebral space 250between them, casing 10 is screwed in through upper vertebral body 100until into lower vertebral body 200, whereby casing 10 passes throughintervertebral space 250. Central area 12 with spreading elements 16comes to rest inside lower vertebral body 200. If screw 20 issubsequently screwed in, spreading elements 16 spread open insidevertebral body 52 in order, for example, to straighten it out andstabilize it.

A stop 26 is arranged on screw shaft 20 a, in particular between centralarea 22 and rear area 23 of screw 20, against which stop the free end ofrear area 13 of casing 10 strikes during the screwing in of screw 20 sothat front area 11 of casing 10 can be drawn against rear area 13 ofcasing 10 and spreading elements 16 spread open in central area 12.

Screw 20 is cannulized so that during the implantation a guide wire 30can be introduced at first via which easing 10 and finally screw 20 cansubsequently be introduced.

FIGS. 7 to 10 show another exemplary embodiment of a casing 10′ that canbe inserted without a screw. Casing 10′ is manufactured from a memorymetal, in particular nitinol, which changes its form in particular uponreaching the body temperature. Casing 10′ has slots 15 also running inthe longitudinal direction between which spreading elements 16 areformed. After casing 10′ has been inserted into vertebral bodies 100,200 and the body temperature reached, front section 11 and rear section13 move relatively toward one another so that spreading elements 16 arespread open in central area 12 (cf. FIG. 8). Casing 10′ is stabilizedthereby in vertebral body 200 via outer threading 14 of front area 11.

A third exemplary embodiment of a casing 10″ is shown in FIGS. 11 to 16.Casing 10″ has slots 15″ that extend in the longitudinal direction butrun at an incline to the longitudinal direction. If front area 11 andrear area 13 are moved toward one another and in particular are rotatedrelative to one another at this time, spreading elements 16 formedbetween slots 15″ spread open, whereby they remain almost resting on oneanother in particular during the rotation of front section 11 againstrear section 13 and form a circumferential bead (cf. FIG. 15).

FIGS. 19 to 21 show how casing 10′ comes to rest in the adjacentvertebral bodies 100, 200. Casing 10′ is introduced through uppervertebral body 100, passes through intervertebral space 250 and isintroduced so far that front area 11 and central area 12 come to rest inlower vertebral body 200. Spreading elements 16 stabilize lowervertebral body 200 after the spreading open of casing 10′.

The stabilizing element can therefore be formed from a casing such as,for example, casing 10 or 10′ in combination with a bone screw, forexample, bone screw 20, or solely from one casing such as, for example,casing 10″, or also solely from one bone screw such as, for example,bone screw 20.

If the stabilizing element is formed exclusively by a bone screw, thebone screw can have a pitch over its entire length. In a preferredembodiment of the invention, bone screw 20 has a shaft 20 a and a head20 b, which shaft 20 a has a front section 21, a following central area22 and following rear section 23, which rear section 23 is followed byhead 20 b (cf. FIG. 4). A first outer threading 24 is arranged in frontsection 21 of screw 20 whereas a second outer threading 25 is arrangedin rear section 23. First outer threading 24 has a third pitch, whereassecond outer threading 25 has a fourth pitch. The third pitch and thefourth pitch are selected differently so that screw 20 acts as atraction screw or compression screw by means of which the relativeposition of the two adjacent vertebral bodies 100, 200 can be variedrelative to one another.

FIGS. 55 to 57 show another exemplary embodiment of a casing 10′″ withanother exemplary embodiment of a screw 20′. FIGS. 58 to 62 show howcasing 10′ and screw 20′ are introduced into two adjacent vertebralbodies 100, 200.

FIGS. 55 to 57 show different views of a first exemplary embodiment of acasing 10′″ with the front section 11 and a following rear area 13.Front area 11 carries an outer threading 14. An inner threading 16 forthe first pitch is arranged in rear section 13. Rear section 13 can beconically designed for better stabilization.

Screw 20′ has a front section 21 and a following central area 22followed by rear section 23. A first outer threading 24 is arranged infront section 21 of screw 20 whereas a second outer threading 25 isarranged in rear section 23. The first outer threading 24 has a thirdpitch, whereas second outer threading 25 has a fourth pitch. However,the fourth pitch of the second outer threading 25 corresponds inparticular to the first pitch of the first inner threading 16 of casing10. The third pitch and the fourth pitch can be differently selected.

As can be recognized in FIGS. 58 to 62, at first screw 20′ isintroduced, in particular along a guide wire 30, into vertebral body100, 200, whereby screw 20′ is screwed through upper vertebral body 100until into lower vertebral body 200, whereby screw 20′ passes throughintervertebral space 53. The central area 12 comes to lie inintervertebral space 53 (cf. FIGS. 58 and 59). Subsequently, casing 10′″is rotated onto screw 20′ (cf. FIGS. 59 to 62), during which secondouter threading 25 of screw 20′ engages into inner threading 16 ofcasing 10″. Casing 10′″ can, in particular, be screwed in so far that astop 26 of screw 20′ is drawn against the distal edge of casing 10′″ andvertebral bodies 100, 200 are subsequently distracted (cf. FIGS. 59, 60and 61). Alternatively, casing 10′″ can also be screwed on only so farthat it remains in superior vertebral body 100 and only the centralsection 22 of screw 20′ passes through intervertebral space 53 (cf. FIG.62).

In one embodiment central section 22 of screw 20′ is elasticallyconstructed. If casing 10′″ is screwed on only so far that it remains insuperior vertebral body 100, and only the central section 22 of screw20′ passes through intervertebral space 53, there is the possibility oftilting vertebral bodies 100, 200 toward one another and moving themrelative to one another so that an intervertebral disk can be simulatedin this manner (cf. FIG. 62).

A good stabilization of the two vertebral bodies 100, 200 relative toone another can be achieved in particular given the formation of bonescrew 20 as compression screw, especially if an intervertebral diskprosthesis is additionally introduced into intervertebral space 250.

Embodiments of an intervertebral disk prosthesis are described in thefollowing.

FIG. 22 shows a top view onto first exemplary embodiment of anintervertebral disk prosthesis 1000 with a first shank 1100 that has afirst end 1100 a and a second end 1100 b and has a second shank 1200that has a first end 1200 a and a second end 1200 b. The two shanks1100, 1200 are connected to each other in one piece on their second ends1100 b, 1200 b. The free ends 1100 a, 1200 a are bent toward one anotherso that an almost closed ring with a slot results. Intervertebral diskprosthesis 1000 is manufactured from an elastic material, which makes itpossible that the two shanks 1100, 1200 can be pivoted toward oneanother. The pivoting of the two shanks 1100, 1200 toward one anothertakes place in the plane in which the U-shaped element lies. In thepresent instance this is in particular the paper plane.

FIG. 23 shows a top view onto a second exemplary embodiment of anintervertebral disk prosthesis 2000 with a first shank 2100 that has afirst end 2100 a and a second end 2100 b and with a second shank 2200that has a first end 2200 a and a second end 2200 b. The first ends 2100a, 2200 a are designed as free ends whereas the two shanks 2100, 2200are connected to each other on their second ends 2100 b, 2200 b. Thisconnection takes place by a bolt 2500. In the exemplary embodimentaccording to FIG. 23, the two shanks 2100, 2200 are directly supportedagainst one another in a rotatable manner by a single bolt 2500.Alternatively, it is also possible to arrange each of the two shanks2100, 2200 pivotably on a connection element by a separate bolt. Bolt2500 runs substantially vertically to the plane of substantiallyU-shaped intervertebral disk prosthesis 2000, in particular verticallyto the paper plane in the drawing. As a result, the two shanks 2100,2200 are pivotably supported against one another in the plane ofU-shaped intervertebral disk prosthesis 2000, i.e., in the paper plane.A pivoting open of the two shanks 2100, 2200 toward one another can takeplace, for example, in that a spreading-open element 2600 of a holder2700 is thrust between the two shanks 2100, 2200 and that the two shanks2100, 2200 are formed with such a compulsory curve on their second ends2100 b, 2200 b that they escape from spreading-open element 2600 and arepivoted relatively toward one another.

FIG. 24 shows a top view onto a third exemplary embodiment of aintervertebral disk prosthesis 3000 with a first shank 3100 that has afirst end 3100 a and a second end 3100 b and with a second shank 3200that has a first end 3200 a and a second end 3200 b. The two shanks3100, 3200 are arranged pivotably supported against one another viable3500 similar to the second exemplary embodiment of the intervertebraldisk prosthesis 2000, whereby bolt 3500 runs substantially vertically tothe plane of the substantially U-shaped intervertebral disk prosthesis3000, i.e., substantially vertically to the paper plane in the presentrepresentation. A pivoting open of the two shanks 3100, 3200, relativeto one another, takes place in the third exemplary embodiment by meansof a lever element 3600 arranged on intervertebral disk prosthesis 3000.Lever element 3600 is also supported in such a manner that it can pivotabout bolt 3500 and is constructed, for example, as an eccentricelement. During the pivoting of lever element 3600 in pivoting directionX, lever element 3600 attacks, for example, a compulsory curve 3700arranged on second end 3100 b of first shank 3100 in order to pivot thetwo shanks 3100, 3200 apart for one another in pivoting direction Y. Acorresponding compulsory curve can also be arranged on free end 3200 bof second shank 3200 which curve brings about a pivoting apart of thetwo shanks 3100, 3200 during the pivoting of lever element 3600 aboutbolt 3500.

FIG. 25 shows a top view onto a fourth exemplary embodiment of anintervertebral disk prosthesis 4000 with a first shank 4100 that has afirst end 4100 a and a second end 4100 b and with a second shank 4200that has a first end 4200 a and a second end 4200 b, whereby the twoshanks 4100, 4200 are connected to one another by a cylindricalarticulation 4500. An actuation element 4600 can be inserted intocylindrical articulation 4500 in order to pivot the two shanks 4100,4200 toward one another.

FIGS. 26 to 28 show a fifth exemplary embodiment of an intervertebraldisk prosthesis 5000. Intervertebral disk prosthesis 5000 has a firstshank 5100 and a second shank 5200, which first shank 5100 has a firstend 5100 a and a second end 5100 b whereas the second shank 5200 has afirst end 5200 a and a second end 5200 b. The two shanks 5100, 5200 areconnected to one another on their second ends 5100 b, 5200 b by aconnecting element 5300, The first shank 5100 is pivotably supported bya bolt 5300 a on connecting element 5300 whereas second shank 5200 ispivotably supported by a bolt 5200 b on connecting element 5300.Furthermore, the two ends 5100 b, 5200 b of shanks 5100, 5200 areequipped with a geared section 5100 c, 5200 c, which geared sections5100 c, 5200 c are arranged in particular concentrically around theparticular bolts 5300 a, 500 b. During the introduction ofintervertebral disk prosthesis 5000 into an intervertebral space, thetwo shanks 5100, 5200 lie substantially parallel (compare FIG. 26).After the introduction of intervertebral disk prosthesis 5000 into theintervertebral space, a spreading-open element 5600 is introducedbetween the two second ends 5100 b, 5200 b of shanks 5100, 5200.Spreading-open element 5600 has a geared section 5700 corresponding togeared sections 5100 c, 5200 c of shanks 5100, 5200 by means of whichgeared section 5700 the two shanks 5100, 5200 are spread further apartthe further spreading-open element 5600 is introduced between the twoshanks 5100, 5200.

In order to be able to visually follow the introduction and positioningof intervertebral disk prosthesis 5000 in the intervertebral space, inparticular the first ends 5100 a, 5200 a are provided with an x-raycontrast material, for example, coated with tantalum. Another x-raycontrast marker is preferably arranged in the third place. Preferably,at least three x-ray contrast markers are arranged on intervertebraldisk prosthesis 5000 that also do not necessarily have to be arranged onthe free ends 5100 a, 5200 a of shanks 5100, 5200. Of course, the x-raycontrast markers can also be used with all other intervertebral diskprostheses described in the present Application.

Shanks 5100, 5200 each have a recess 5100 d, 5200 d on the lateralsurfaces facing each other. In particular a bone screw that stabilizestwo adjacent vertebral bodies against one another can be run throughthis area.

As can be recognized in the lateral view according to FIG. 27 the upperand lower sides of shanks 5100, 5200 can be designed curved in order toadapt to the anatomic conditions. In particular, the upper and/or lowerside(s) of intervertebral disk prosthesis 5000 can have teeth 5500 inorder to improve an anchoring of intervertebral disk prosthesis 5000 inthe adjacent vertebral body.

The first shank 5100 has in the present instance a larger side thanshank 5200 (compare FIGS. 26 and 28) in order to achieve a uniformstabilization of the two adjacent vertebral bodies against one anotherfor the case that the bone screw connecting the two adjacent vertebraeto one another is not centrally guided through the intervertebral space.

FIGS. 28 to 34 show different views of a sixth exemplary embodiment ofan intervertebral disk prosthesis 6000 whereas FIGS. 35 to 44 show inwhat manner intervertebral disk prosthesis 6000 can be introduced intothe intervertebral space.

Intervertebral disk prosthesis 600 has a first shank 6100 and a secondshank 6200 which first shank 6100 has a first end 6100 a and a secondend 6100 b, whereas the second shank 6200 has a first end 6200 a and asecond end 6200 b. The two shanks 6100, 6200 have a second recess 6100d, 6200 d on the side surface facing the other one between the first end6100 a, 6200 a and between the second end 6100 b, 6200 b. The two shanks6100, 6200 are connected to one another by a spring element 6500 (cf.FIG. 32) that engages, as described in the following, into the secondrecess 6100 d, 6200 d of shanks 6100, 6200. Spring element 6500 has asubstantially cylindrical section 6500 a that is slotted over its entirelength and on which, starting from the slot, two anchoring wings 6500 b,6500 c are arranged. Anchoring wings 6500 b, 6500 c can therefore pivotsubstantially about the longitudinal axis of cylindrical section 6500 aof spring element 6500. One anchoring ring 6500 b, 6500 c at a timeengages into one of the two recesses 6100 d, 6200 d of shanks 6100, 6200(compare in particular FIGS. 30 and 31). Here, FIG. 31 shows the stateof spring element 6500 without outside action of force. Thus, springelement 6500 is relaxed when the two shanks 6100, 6200 are spread openrelative to one another. On the other hand, FIG. 30 shows spring element6500 in the loaded state. The two shanks 6100, 6200 are moved into aclosed position counter to the force of spring element 6500 in whichposition they run in particular substantially parallel to one another.

A first recess 6100 c, 6200 c is arranged between the second recess 6100d, 6200 d and the first ends 6100 a, 6200 a of shanks 6100, 6200 on theside surfaces of shanks 6100, 6200 facing one another, through whichrecesses in particular a bone screw connecting the two adjacentvertebral bodies can be run as a stabilizing element, for example, bonescrew 20 previously described using FIG. 4.

A third recess 6100 e, 6200 e is arranged between second recess 6100 d,6200 d and the second ends 6100 b, 6200 b of shanks 6100, 6200 on theside surfaces of shanks 6100, 6200 facing one another into which thirdrecess an insertion instrument 6600 can engage as described in thefollowing using FIGS. 14 and 15.

Several x-ray contrast markers are arranged on shanks 6100, 6200, inparticular in the area of first ends 6100 a, 6200 a of shanks 6100, 6200and in the area between second recess 6100 d, 6200 d and first recess6100 c, 6200 c in order to be able to follow visually the insertion ofintervertebral disk prosthesis 6000.

FIGS. 35 to 37 show insertion instrument 6600 in detail, which has acasing 6700 in which two holding elements 6800 and a spreading-openelement 6900 are arranged in an axially shiftable manner. Holdingelements 6800 have gripping elements 6800 a on their distal end that areconstructed in the present instance as spheres or cylinders that engageinto fourth recesses 6100 f, 6200 f substantially positively and arearranged on the outer side surfaces of shanks 6100, 6200 which sidesurfaces face away from the particular other shank 6100, 6200. Grippingelements 68001 can lock in recesses 6100 f, 6200 f or be held in them ina clamping manner or only rest in them in a substantially positivemanner. Spreading-open element 6900 has an element 6900 a on its distalend which element can also be constructed as a spherical or cylindricalelement and which engages into third recess 6100 e, 6200 e ofintervertebral disk prosthesis 6000.

As FIG. 35 shows, spring element 6500 is widened against the springforce by the insertion of element 6900 a of spreading-open element 6900into the third recesses 6100 e, 6200 e and the two shanks 6100, 6200 aremoved into a closed position. At the same time, gripping elements 6800 aof holding elements 6800 engage into fourth recesses 6100 f, 6200 f ofshanks 6100, 6200 in order to hold intervertebral disk prosthesis 6000.In this position, intervertebral disk prosthesis 6000 can be introducedbetween two adjacent vertebral bodies 100, 200, as shown in FIGS. 38 and39. In order to spread the intervertebral disk prosthesis open,spreading-open element 6900 is withdrawn axially in casing 6700 ofinsertion instrument 6600 so that shanks 6100, 6200 are spread openrelative to one another by the force of spring element 6500 (compareFIG. 36 and FIG. 40). Intervertebral disk prosthesis 6000 cansubsequently be shifted into the intervertebral space to the desiredposition by holding elements 6800 (compare FIG. 40). Subsequently, evenholding elements 6800 can be separated from intervertebral diskprosthesis 6000 by axially withdrawing holding elements 6800 in casing6700 of insertion instrument 6600 (compare FIGS. 37 and 41) andsubsequently insertion instrument 6600 can be completely removed fromthe operation area (compare FIG. 42). FIG. 43 illustrates in whichmanner a bone screw 20 traversely passes through the intervertebralspace and intervertebral disk prosthesis 6000 in particular in the areaof first recesses 6100 c, 6200 c of shanks 6100, 6200, whereas in FIGS.38 to 43 bone screw 20 is shown only in section. A lateral view of theincorporated situation of intervertebral disk prosthesis 6000 into theintervertebral space between the two adjacent vertebral bodies 100, 200is shown in FIG. 44. In particular, the connection line 70, along whichbone screw 20 connects the two vertebral bodies 100, 200, is shown.

FIGS. 45 to 48 show a seventh exemplary embodiment of an intervertebraldisk prosthesis 7000 that has a first shank 7100 with a first end 7100 aand a second end 7100 b as well as has a second shank 7200 with a firstend 7200 a and a second end 7200 b. The two shanks 7100, 7200 can beconnected to one another to one piece or can be constructed as aseparate shank. Instead of spring element 6500, according to the sixthexemplary embodiment a spring element 7500 consisting of a memory alloyis arranged between the two shanks 7100, 7200. The memory alloy isdesigned in particular in such a manner that the form is changed uponreaching the body temperature. FIG. 45 shows an intervertebral diskprosthesis 7000 with the two shanks 7100, k7200 in the closed position,in which intervertebral disk prosthesis 7000 can be introduced into theintervertebral space. This takes place in particular at a temperaturethat is slightly below the body temperature, in particular at roomtemperature, so that spring element 7500 rests on the two shanks 7100,7200 and, if necessary, additionally supports the holding of shanks7100, 7200 in the closed position. FIG. 46 shows the widening open ofspring element 75 upon reaching the body temperature based on the memoryeffect, whereby spring element 7500 spreads open in such a manner thatshanks 7100, 7200 are pivoted against one another.

Intervertebral disk 7000 can subsequently be moved into the desiredposition in the intervertebral space with an insertion instrument 7600comparable to insertion instrument 6600 in accordance with the sixthexemplary embodiment in order to subsequently remove insertioninstrument 7600, whereby intervertebral disk prosthesis 7000 remains inthe spread-open position by spring element 7500. Spring element 7500 inaccordance with FIGS. 45 and 46 has two elements in the manner ofleaf-spring shanks. Alternatively, as shown in FIGS. 47 and 48, springelement 7500 can also be constructed as a slotted easing with two curvedshanks.

The features from the different exemplary embodiments can also becombined in any desired manner.

Shanks 1100, 1200, 2100, 2200, 3100, 3200, 4100, 4200, 5100, 5200, 6100,6200, 7100, 7200 of intervertebral disk prostheses 1000, 2000, 3000,4000, 5000, 6000, 7000 can all be manufactured from an elastic material.However, shanks 1100, 1200, 2100, 2200, 3100, 3200, 4100, 4200, 5100,5200, 6100, 6200, 7100, 7200, are preferably manufactured from PEEK(polyetheretherketone),

1.-20. (canceled)
 21. A method for accessing an intervertebral spacebetween two adjacent vertebral bodies of a vertebral column, comprising:providing an intervertebral disk prosthesis; identifying a singleextraforaminal access point proximate the intervertebral space; andidentifying an access path from the single extraforaminal access pointto the intervertebral space without intersecting a pedicle or any spacebetween pedicles of the two adjacent vertebral bodies; and introducingthe intervertebral disk prosthesis along the access path into theintervertebral space.
 22. The method as in claim 21, wherein the accesspath is linear.
 23. The method as in claim 21, wherein the singleextraforaminal access point is located more than 4.5 cm laterally awayfrom a sagittal plane.
 24. The method as in claim 21, wherein the accesspath extends proximal to the pedicle or the space between pedicles. 25.The method as in claim 21, wherein the single extraforaminal accesspoint is arranged on a left side of a sagittal plane.
 26. The method asin claim 21, wherein the single extraforaminal access point is arrangedon a right side of a sagittal plane.
 27. The method as in claim 21,further comprising: pressing nerve roots present along the access pathin an inferior-medial direction.
 28. The method as in claim 21, furthercomprising: pressing nerve roots present along the access path in asuperior-lateral direction.
 29. The method as in claim 21, furthercomprising: providing a first fixation screw; introducing the firstfixation screw through the single extraforaminal access point; andattaching the first fixation screw to one of the two adjacent vertebralbodies.
 30. The method as in claim 29, further comprising: providing asecond fixation screw; introducing the second fixation screw through thesingle extraforaminal access point; and attaching the second fixationscrew to a second of the two adjacent vertebral bodies.
 31. The methodas in claim 30, further comprising: fastening a rod between the firstfixation screw and the second fixation screw.